Ive done more research and i think the hose im speaking of is a rear cylinder vent. It is plugged with a screw and i read that it needs be open and not plugged. Any input would be greatly appreciated
yep, that's your crank case breather. unplug that now. should never be just capped off - all the pressure inside the engine is released through that vent.
it used to go to the back of the air cleaner backing plate and the engine sucked in the air pressure generated from the piston's downward travel. in 1972 cars started with the PVC valve, pulled crankcase pressure into the base of the carburetor. understand yours is gone? former owner removed the epa stuff? that's common with these bikes.
look up Grampsize and Scooterize for an 800 vulcan.
see if you can determine if your former owner did it right.
done incorrectly the bike will run like shit.
done correctly the bike goes from about 55HP to about 80HP.
I'm an old HotRod/DragRace guy.
I did a combination of the Gramp/Scooter deal and my bike runs awesome.
43mpg, open exhaust, K&N air filter, larger jets and needle in the carb.
bike gets up and goes and will easily hit the rev limiter in every gear.